The invention relates to a liquid coating composition based on a compound containing an activated CH group and an .alpha.,.beta.-ethylenically unsaturated carbonyl compound.
A coating composition of the type indicated above is known from, int. al. German Patent Specification No. 835,809. As compounds containing an activated CH group, it proposes acetoacetates, acetoacetamides and cyanoacetates.
Examples of suitable .alpha.,.beta.-ethylenically unsaturated carbonyl compounds include acrylic or methacrylic esters or amides. In practice, however, it has been found that these well-known compositions can generally be insufficiently cured at room temperature and special steps must therefore be taken for the object coated with such a composition to be heated to the elevated temperature desired. This is a drawback, particularly in the case of, for instance, large steel structures.
It should also be noted that a coating composition based on an epoxy resin to be cured with a polyamine is curable at room temperature, but the resulting coatings display insufficient stability of gloss upon outdoor exposure. Further, compositions based on a polyisocyanate and a suitable hydroxy compound may cure at room temperature, but polyisocyanates may impair health, and can therefore be used only when taking special precautions.